Infestation!

Head to Baaluk and you'll find the pub's owner seated at a table left of the bar. Talk to him and he'll tell a tale of woe as you hear the sound of insects buzzing in the background. They're ruining business, and they come from the east. You're asked if you'd be interesting in destroying the hive from which they continue to pour. Answer "Squashing bugs, huh? I'm in." to accept the task. You'll be sent to the battlefield at Salamander's Tail.

Waiter, how did this fly get in my soup?

The queen is the toughest of the bunch, naturally.

This quest is actually just a boss battle. As it begins, there are seven enemy units on the field. Start as you usually would: by taking down one unit at a time (though first you'll have to close in on them). None of them should prove difficult. An offensive rush may be enough to tend to all of them within two turns and without the need to stop for healing. When you've rid the field of the first seven groups, an additional four will arrive as reinforcements. Repeat the same strategy that worked on the first wave, though the new arrivals are of a heartier breed. They'll soon be joined by three more enemy unions, as well (right as the turn commences), so be prepared for that.

The second wave will continue to arrive in pieces, with six more unions arriving on the scene as you're tending to their cohorts. Among them should be the unions that guard the queen, plus she herself will make the expected appearance. At this point, you should be watching your health, which by now may have been worn down to the point where it can cause some concern. Make sure that you get your health up for this final leg of the battle and focus on eliminating the weaker units so that you can pay more attention to the queen herself. The Queen's guard groups are capable of using a powerful 'Cacophony' attack that will curse party members, so focus on defeating them first. Keep up your health, hit hard and you should be able to face the queen in fairly good shape. Though her life meter is lengthy, she's easy enough to defeat once her guards are out of the picture.

Once you win, you'll be returned to the pub for your reward (the keeper gives you Empty Aerial Insecta Shell and 10,000G, on top of the reward linked to the quest) and your job is complete.